History of medicine on the Internet: resources for librarians

This paper offers an inventory of resources on the history of medicine on the Internet. Some sites are bibliographic; they supply book and journal citations. Some provide leads (or links) to more specific information, and some include full-text articles or historical essays. Because this material is intended to furnish librarians with reference direction, more attention is given to bibliographic and "linked" sites.     

在教学中对学生创造力的培养

在教学中对学生创造能力的培养,可从以下几方面进行探索。一、设置问题情景设置问题情景,激发学习兴趣和创造欲望,启发学生提出问题（或感受问题）,提出假说,检验假说,发表认识成果,开展创造性教学。创设好的问题情景能激发学生的好奇心和求知欲。问题情景的创设和...     

The locus of focus: the effect of switching from a preferred to a non-preferred focus of attention

Focusing strategies are known to play a significant role in motor performance, with individuals who use an internal focus on body movement typically showing poorer outcomes than those who focus on features of the external environment. Focus of attention and switching of one's focus are examined in the context of two different complex motor skills along with a factor not previously examined systematically, individual preference. In both experiments, participants were introduced to focusing strategies that might be employed when attempting a sensorimotor task. Explanations of both strategies were given to participants. Specifically, for an internal focus, participants were instructed to concentrate on their body movements, while for an external focus, they were instructed to focus on aspects in the environment. They were then asked which strategy they preferred. Participants then continued either with their preferred focus or were instructed to switch to their non-preferred focus. The advantage that the external focus typically enjoys turns out not to be a simple one and interacts with individual preference and with the "forced-opposite" manipulation. Our results support the growing consensus that encouraging individuals to adopt an internal focusing strategy is counterproductive in complex sensorimotor tasks. They also suggest that individual preferences play a role.     

A comparison of modelling and imagery in the acquisition and retention of motor skills

Although many researchers have examined the effects of imagery and/or modelling interventions, it is unclear which of the two interventions is more effective. In two experiments, novice learners assessed over multiple trials of a free weight squat lifting or a stabilometer balancing task were given modelling, imagery, a combination of modelling and imagery, or control interventions. Group differences indicated, in general, that groups receiving modelling (modelling, combination) evidenced a more appropriate form than groups that did not receive modelling (imagery, control). When apparent, these differences were already in place after the first of several interventions. Practical implications are that even a single bout of modelling can have immediate beneficial effects on movement form (Experiments 1 and 2) and outcome (Experiment 1).     

Acute effects of static stretching on characteristics of the isokinetic angle - torque relationship, surface electromyography, and mechanomyography

The aims of this study were to examine the acute effects of static stretching on peak torque, work, the joint angle at peak torque, acceleration time, isokinetic range of motion, mechanomyographic amplitude, and electromyographic amplitude of the rectus femoris during maximal concentric isokinetic leg extensions at 1.04 and 5.23 rad x s(-1) in men and women. Ten women (mean +/- s: age 23.0 +/- 2.9 years, stature 1.61 +/- 0.12 m, mass 63.3 +/- 9.9 kg) and eight men (age 21.4 +/- 3.0 years, stature 1.83 +/- 0.11 m, mass 83.1 +/- 15.2 kg) performed maximal voluntary concentric isokinetic leg extensions at 1.04 and 5.23 rad x s(-1). Following the initial isokinetic tests, the dominant leg extensors were stretched using four static stretching exercises. After the stretching, the isokinetic tests were repeated. Peak torque, acceleration time, and electromyographic amplitude decreased (P< or = 0.05) from pre- to post-stretching at 1.04 and 5.23 rad . s(-1); there were no changes (P > 0.05) in work, joint angle at peak torque, isokinetic range of motion, or mechanomyographic amplitude. These findings indicate no stretching-related changes in the area under the angle - torque curve (work), but a significant decrease in peak torque, which suggests that static stretching may cause a "flattening" of the angle - torque curve that reduces peak strength but allows for greater force production at other joint angles. These findings, in conjunction with the increased limb acceleration rates (decreased acceleration time) observed in the present study, provide tentative support for the hypothesis that static stretching alters the angle - torque relationship and/or sarcomere shortening velocity.     

The exercise and affect relationship: evidence for the dual-mode model and a modified opponent process theory

This study examined the relationship between exertion level and affect using the framework of opponent-process theory and the dual-mode model, with the Activation-Deactivation Adjective Checklist and the State Anxiety Inventory among 14 active and 14 sedentary participants doing 20 min of treadmill exercise at speeds of 5% below, 5% above, and at lactate threshold (LT). We found a significant effect of time, condition, Time × Condition, and Time × Group, but no group, Group × Condition, or Time × Group × Condition effects, such that the 5% above LT condition produced a worsening of affect in-task compared with all other conditions whereas, across conditions, participants experienced in-task increases in energy and tension, and in-task decreases in tiredness and calmness relative to baseline. Posttask, participants experienced mood improvement (decreased tension, anxiety, and increased calmness) across conditions, with a 30-min delay in the above LT condition. These results partially support the dual-mode model and a modified opponent-process theory.     

Anthropometric and kinematic influences on release speed in men's fast-medium bowling

The main aim of this study was to identify significant relationships between selected anthropometric and kinematic variables and ball release speed. Nine collegiate fast-medium bowlers (mean +/- s: age 21.0 +/- 0.9 years, body mass 77.2 +/- 8.1 kg, height 1.83 +/- 0.1 m) were filmed and reconstructed three-dimensionally. Ball release speeds were measured by a previously validated Speedchek Personal Sports Radar (Tribar Industries, Canada). Relationships between selected anthropometric variables and ball release speed and between kinematic variables and ball release speed were investigated using Pearson's product-moment correlation coefficients (r). A significant relationship was found between the horizontal velocity during the pre-delivery stride (r = 0.728, P < 0.05) and ball release speed (31.5 +/- 1.9 m(-1) s(-1)). We believe that the high correlation was due to the bowlers using techniques that allowed them to contribute more of the horizontal velocity created during the run-up to ball release speed. We also found that the angular velocity (40.6 +/- 3.4 rad x s(-1)) of the right humerus had a low correlation (r = 0.358, P > 0.05) with ball release speed. Although the action of the wrist was not analysed because of an inadequate frame rate, we found high correlations between ball release speed and shoulder-wrist length (661 +/- 31 mm; r = 0.626, P < 0.05) and ball release speed and total arm length (860 +/- 36 mm; r = 0.583, P < 0.05). We conclude that the variance in release speed within this group may be accounted for by the difference in radial length between the axis of rotation at the glenohumeral joint and the release point.     

Effect of Oxidized Phosphatidylcholine on Biomarkers of Oxidative Stress in Rats

In this study it was planned to investigate the effect of oxidized phosphatidylcholine (derived from egg) feeding on lipid peroxidation of different tissues in rats. Male Wistar albino rats were fed oxidized and unoxidized phosphatidylcholine for 2 and 4 weeks, respectively. During the period of study food intake and body weights of animals increased gradually. Animals fed oxidized phosphatidylcholine for 2 and 4 weeks showed 33 and 15% spontaneous hemolysis of red blood cells in vitro. Under identical experimental conditions animals given unoxidized phosphatidylcholine showed 14.5 and 13.4% hemolysis for 2 and 4 week’s period, respectively. Thiobarbituric acid reactive substances (TBARS) level in thymus, spleen, kidney, heart, liver and lung significantly increased in rats given oxidized phosphatidylcholine as compared to unoxidized group. Furthermore, in oxidized phosphatidylcholine group TBARS values in kidney, liver and lungs continued to rise for 4 weeks of treatment while TBARS level in heart, spleen and thymus was found to be decreased at the end of 4 weeks of oxidized phosphatidylcholine feeding. Plasma triacylglycerol and cholesterol was found to increase in rats who had received oxidized phosphatidylcholine for 2 weeks. These findings suggest that excess and persistent intake of oxidized phosphatidylcholine can cause significant damage to organs.